Tapered sheet metal nail



Sept. 16, 1969 R. L. HALLOCK TAPERED SHEET METAL NAIL 2 Sheets-Sheet l Filed March l2, 1968 f www.

Sept. l6, 1969 R.L..HA1 ocK 3,455,967

TAPERED SHEET METAL NAIL v Filed March 12, 196s 2 sheets-Sheet n INVENTOR TLHALLC/f United States Patent O U.S. Cl. 85-11 5 Claims ABSTRACT OF THE DISCLOSURE A tapered sheet metal nail having a head portion and hollow shank portion extended therefrom and terminating in an enlarged remote penetrating end, such shank portion being longitudinally split and the split edges overlapping whereby when the nail is driven into precast or poured lightweight aggregate compositions, such as gypsum, its penetrating end will expand and receive and retain therein a relatively large connection-forming plug which remains in the nail to keep it expanded, thus offering maximum resistance to the Withdrawal of the nail.

BACKGROUND OF THE INVENTION Field of the invention This invention is in the special type of nail art in which the nail is employed for fastening relatively soft material, such as roofing felt and the like, to a somewhat rmer base such as poured or precast gypsum type roof.

Description of the prior art Various kinds of nails have been produced of many types of materials, including sheet metal, and with expandable portions intended to provide solid connections. These nails have not been satisfactory for securing roofing, roofing felt, insulation, and the like, to poured and precast roof decks of gypsum, vermiculite, perlite, and the like, mainly because their expandable parts or portions contracted easily and offered little resistance to Withdrawal and consequently have inadequate holding power. Cut and bright nails have also been used which have proven satisfactory after they have had opportunity to rust in the poured decks during drying. This hardening and rusting has required up to four weeks time during which, if there were a high wind, the roofing felt and other material has been known to blow olf or become loose, partially withdrawing and raising the heads of the cut nails above the deck surface where they rust and also eventually cause puncturing of the rooting overlying the same.

SUMMARY OF THE INVENTION The present invention is a tapered sheet metal nail of a character to expand when driven and having a head portion and a hollow shank portion extending therefrom and terminating in a remote penetrating end substantially larger than the portion of the shank which joins the head. Also the shank portion is longitudinally split and such split edges overlapped so that when the nail is driven its penetrating end will expand into outwardly gripping relation with the material into which driven and receive therein enough material to lill the same and prevent contraction of the expanded penetrating end so that such nail will offer maximum resistance to its withdrawal.

It is an object of the invention to provide a nail having adequate holding power from the time it is driven, with such holding power far greater than anything heretofore obtainable due to the nail having a self-expanding conlined truncated cone shaped shank which on driving expands at the driven or penetrating end and the shank is -filled with the material into which it is driven. Also, on withdrawal of the nail the mass of material within the 3,466,967 Patented Sept. 16, 1969 ICC shank breaks away and remains in the shank and keeps the shank from closing and returning to its original shape ybefore it had expanded.

Other objects and advantages of the invention will be apparent from the following description considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation illustrative of one embodiment of the invention;

FIG. 2, a plan view of the head end of the nail of FIG. 1;

FIG. 3, a horizontal section on the line 3-3 of FIG. 1;

FIG. 4, an elevation of the knurled sheet used in forming the shank of the nail;

FIG. 5, an interior perspective of a fragment of a slightly different form of sheet for use in producing the shank;

FIG. 6, a view of the nail after it has been driven, the nail being in side elevation and the material into which it is driven in section;

FIG. 7, a horizontal section on the line 7-7 of FIG. 6;

FIG. 8, a view similar to that of FIG. 6 with the nail partly withdrawn;

FIG. 9, a side elevation of a modified form of nail;

FIG. 10, an elevation of the penetrating end of the nail of FIG. 9;

FIG. 11, a side-by-side diagrammatic illustration of three other nails and applicants nail after being driven;

FIG. 12, an elevation of the penetrating end of the nails of FIG. 11; and

FIG. 13, an illustration of the nails pulled from the material in which they were driven in FIG. 11 with the shanks of the second and third nails contracted by their withdrawal.

DESCRIPTION OF THE PREFERRED EMBODIMENT The nail of the present invention is designed primarily for more securely fastening the first layer or rooiing felt to a freshly poured or precast roof deck of gypsum, vermiculite, perlite, or the like. The nail is comprised of a head portion 10 and a tubular or truncated cone shaped or tapered shank portion 11, the small end 12 of which is ared or spun over the head portion, and such shank portion has a split 13 from the smaller end adjacent the head to the larger penetrating end 14 with the split edges 13 overlapping. The manner of attaching the smaller end of the shank portion to the head portion by flaring or bending it over prevents such smaller end from expanding when the nail is driven into the freshly poured roof deck of the character indicated or the like.

The nail of the present invention may be made of sheet metal or plastic and it has been found that the nail shank functions best when it is made from .007 inch to .012 inch thick sheet metal approximately 11/2 inches long and with a 1%. inch diameter head fastened as illustrated in FIGS. 1 and 6 when driven into poured gypsum. When thinner metal is used, the cone shaped shank portion 11 expands more easily when driven, but by the same taken the thinner metal shank portions cannot be successfully driven into materials such as partly frozen poured gypsum or other material.

It has been found that the included angle in the tapered or cone-shaped portion should be between 5 and 15 for best performance. This angle also bears a relationship to the thickness of the material used in obtaining the desired amount of expansion when the nail is being driven. Also it has been found that the shank portion 11 may be of various transverse configurations, including round, oval, hexagon, or other configuration, providing that the sheared edges 13 overlap each other.

In the manufacture `of the present type of nail, a segr,

ment of thin sheet metal is rolled into a segment of a truncated cone or tapered tube with a lengthwise split 13, the side edges of which tubular surface overlap each otherA a suicient amount that they remain overlapping in all or most part after the shank portion 11 has expanded while being driven.

The head portion of the nail preferably is made from a thin washer with circular corrugations for adding strength and with the center opening 16 flared upwardly (see FIGS. 1 and 6) or axially to form a very short segment of a tubular cone to facilitate the entrance of the tapered tube and for added strength. The small end of the shank portion 11 is inserted through the hole in the head portion through the opening in the head portion and then flared over in a manner to confine the small end of the shank portion and limit it from expanding when the nail is driven, so that the penetrating larger end 14 receives the material 17 into which the nail is driven within the same. The connection between the shank 11 and head portions 10 is strengthened against separation when the nail is pulled by having the opening flare upwardly in the head portion, thus providing a relatively large area of contact between the head and the shank.

In the use of the nail as it is driven into precast or poured lightweight aggregate compositions 17, such as poured gypsum, vermiculite, perlite, or the like, the tubular tapered or truncated cone-shaped shank portion 11 of the nail progressively expands at its larger penetrating end portion 14 while such portion becomes filled tightly with a mass or plug of the material contained therein. On withdrawal of the nail the larger end of the shank portion remains expanded. This is because the plug of gypsum or other material that was forced into the tube during driving becomes detached from the gypsum or other material into which it is driven and remains inside the expanded shank portion of the nail as the latter is withdrawn.

In view of the fact that the overlapping edges 13 of the shank portion remain overlapping, or substantially so, after the nail has been driven, the plug of gypsum, or other material, within the nail will not ooze out laterally or form a connecting segment of gypsum between the plug and the mass of gypsum to keep the plug from breaking away and staying within the tubular shank and let the shank partly contact as it would if the overlapping edges of the nail did not remain substantially in overlapping relation.

In Order that the shank of the nail may grip more firmly the material into which it is driven and offer maximum resistance to withdrawal of the material Within the expanded shank of the nail as illustrated in FIG. 4, the shank 11 which forms the nail shank may have knurlng 11 or, if preferred, instead of the knurling 11a it may have end struck portions 11b, as illustrated in FIG. 5.

In FIG. 9 is disclosed a slightly different form of vnail having a generally cylindrical shank 11 with an integral flanged or rolled over head portion 12. The shank has a longitudinal split 13', a penetrating end 14', and a generally flared end portion 18. This type of nail possesses generally the characteristics of the nail of FIGS. l and 6, although it is not as satisfactory.

In FIG. 6 the preferred form of nail is illustrated after it has been driven into the poured or precast material for holding the roof felt or the like 19. It will be readily appreciated from a comparison of FIGS. 6 and 8 with the nail of FIG. 1 that the shank has expanded so that the diameter of the penetrating end is greater after it is driven than before and consequently a greater mass of material 17 is contained within the frusto-conical interior of the shank.

In FIG. 8 a tool 20 has been employed to partially withdraw the shank of the driven nail, and due to' the mass of the material contained within the shank, substantial resistance to the retraction is offered so that the 4 material 17 surrounding the shank is distorted upwardly as a result of the force exerted by the tool 20 in a direction away from the material into which the nail was driven.

In FIGS'. ll, 12, and 13, there are diagrammatically illustrated side-by-side comparisons of four different type nails the third and fourth of whichare applicants nails. The first of these nails has a head 21 and a shank 22, the sides of which are generally at right angles to the plane of the head except for a tapered side edge 23 of the nail to facilitate penetration. Prior to the formation of rust which requires substantial time as well as moisture and which rust will increase resistance, all that retains this nail in the material 17 is friction between the nail and the material, and `on actual test the resistance was around five pounds.

The second of these nails includes an indentical head 21 and a pair of legs 24 with notches 25. These legs are curved in cross-section as shown in FIG. 12 and when the nail is driven the legs spread apart but when the nail is withdrawn there is very little holding power as the legs may readily contract or return to their original position. There is, however, a gripping action in addition to friction which in actual test was found to be around fifteen pounds. Unlike in the first instance where only one hole was left, two holes are left in the material in which the nail was driven, but the nail returns to its substantial shape.

In the third embodiment the same head was employed as in applicants nail, the shank 26 being tapered somewhat similar to applicants preferred form of nail of FIGS. l and 6 but with spaced longitudinal edges 27. Consequently, when this nail was driven it expanded, but when it was withdrawn it contracted, leaving a plug of the material into which it was driven and was found to offer a resistance of only 20 pounds. The reason for this was because the plug of material into which it was driven remained connected to the adjacent material through the open slot in the side of the tapered shank. Applicants nail to the extreme right of the figure was found to offer a resistance to withdrawal of 60 to 70 pounds. Also, when applicants nail was withdrawn the mass of material within the shank was coupled so tightly with the shank that the action of withdrawal caused it to become detached from the mass of material into which the nail was driven and consequently the nail was not able to Contact to its original condition as was the case with the three preceding nails.

It will be apparent from the foregoing that a relatively simple practicable nail is provided which may be readily driven through material as described and will have a substantial holding effect without the necessity for the nail to rust and the degree of holding effect may beincreased by treatment to increase the friction or holding ability and in actual use has lbeen tried and accepted by the trade.

It will be obvious to one skilled in the art that various changes may be made in the invention without departing from the spirit and scope thereof and therefore the invention is not limited by that which is illustrated in the drawing and described inthe specification.

What is claimed is:

1. A two-part nail for driving into relatively soft material comprising a head portion and a shank portion in the form of a hollow sleeve split lengthwise throughout its axial length with one end portion thereof received within and retained by said head portion, the edges of said split being in limited overlapping relation with each other, the internal and external surfaces of said sleeve on at least the end portion thereof remote from said head providing frusto-conical surfaces with the larger end thereof defining the free end of said sleeve and constituting an enlarged penetrating extremity, whereby when the nail is driven the penetrating end portion will expand and receive therein a plug which will remain within the shank and prevent the latter from contracting upon withdrawal thereby providing a connection oering maximum resistance to withdrawal.

2. The structure of claim 1 in which said shank portion has an expanded engagement with said head portion.

3. The structure of claim 1 in which the edges of the shank -along the longitudinal split overlap each other at least adjacent the penetrating end portion.

4. The structure of claim 1 n which the hollow shank has its surfaces modified to increase its friction.

5. The structure of claim 1 in which the hollow shank is modified to increase its gripping of a mass of material received therein when the nail is driven and to resist said mass and shank from separating on withdrawal of the nail.

References Cited UNITED STATES PATENTS 795,553 7/1905 Sherman 85-10 969,550 9/1910 McGee tss-11 1,802,270 4/1931 Rawurrgs ssss 2,321,101 6/1943 opemhaw s511 3,094,344 6/1963 Varga 85-83 FOREIGN PATENTS 236,708 3/ 1964 Austria. 948,459 8/ 1956 Germany.

RAMON s. BRITTS, Primary Examiner U.S. Cl. X.R. 52--362; 85-28 

